PV panel circuit breaker

[cmcmill01]

Hi,
Any body recommend a DC circuit breaker for some PV Panels to be connected into my solar controller? Has to be surface mounted onto some wood. Got 2 x 50w panels in paralllel.
Cheers
Craig

 

[moggy1968]

I don't know about on vehicles, but on domestic supplies, which carry around 600v, we don't fuse them because the fault current is almost the same as the operating current.

The difference I suppose is that to short a domestic system, the +ve and -ve would have to physically touch, so we keep the cables seperated, wheras on the vehicle if the +ve chaffs through it will short on the vehicle bodywork as thats the earth (-ve)

 

[StarCruiser]

Hi,
Any body recommend a DC circuit breaker for some PV Panels to be connected into my solar controller? Has to be surface mounted onto some wood. Got 2 x 50w panels in paralllel.
Cheers
Craig

What voltage? And as with the last post, there may be a nuisance tripping factor. I can see the logic behind not fusing/ fitting a breaker if there is no current above the operating current left to blow a fuse or trip a trip. This being the case, I would just add protection to any cables that could become damaged and not fuse though beyond the last post, I have no experience of solar except that they are not fused but run in single cables.

 

[cmcmill01]

The MC4 connectors talk about isolation before disconnecting, so was looking for some kind of circuit breaker, although didn't stop me using them over the weekend down in Dorset

 

[StarCruiser]

Ahh, right, now I see where you're coming from.
What they are concerned about is initiating a DC arc upon disconnection. In other words, they are advising to switch the load off before disconnecting. Good advice as you don't want a DC arc in your hand.

Something from this page may be the sort of thing. http://uk.rs-online.com/web/c/autom...67374613D44432069736F6C61746F7226&r=f&sra=oss

Alternately, do the panels fold face to face? If so do that first, you're effectively shutting them off.

 

[cmcmill01]

Ahh, right, now I see where you're coming from.
What they are concerned about is initiating a DC arc upon disconnection. In other words, they are advising to switch the load off before disconnecting. Good advice as you don't want a DC arc in your hand.

Something from this page may be the sort of thing. http://uk.rs-online.com/web/c/autom...67374613D44432069736F6C61746F7226&r=f&sra=oss

Alternately, do the panels fold face to face? If so do that first, you're effectively shutting them off.

cheers those are just what I was looking for. Panel folds so the panels are on the outside

 

[StarCruiser]

cheers those are just what I was looking for. Panel folds so the panels are on the outside

Wrap them in a black sheet or carry bag and they won't be generating any significant current.

 

[moggy1968]

Wrap them in a black sheet or carry bag and they won't be generating any significant current.

DC electrics can arc really badly, thats why they say to isolate before pulling apart the connectors, but as above, just cover the panels, then there's no power, then there's no problem.
The alternative is just to put the cables into a DC isolator. They are available from most commercial electrical outlets thanks to the domestic PV market, but they are a bit bulky and it's probably just a bit OTT really.

 

[moggy1968]

Your not far from me (Tadworth) and I still have loads of PV cable, MC4s and the correct crimping tool so if you need a hand with anything just let me know. happy to let you have some connectors if you need them